1. Field of the Invention
The present invention relates to a method for thawing a food in a microwave oven, and more particularly to a food thawing method involving a procedure of turning a food by a user upon thawing the food, capable of preventing the food from being partially boiled and thereby achieving an optimum thawing.
2. Description of the Background Art
Referring to FIG. 1, there is shown a thawing device equipped in a microwave oven. As shown in FIG. 1, the thawing device includes a heating chamber 1 for heating a food 2 disposed therein. A turntable 3 is rotatably disposed in the heating chamber 1. The turntable 3 supports the food 2 thereon. Beneath the turntable 3, a weight sensor 4 is disposed which serves to sense the weight of food 2 laid on the turntable 3. The thawing device further includes a microcomputer 5 for calculating a thawing time for the food 2 based on an output signal from the weight sensor 4 and controlling various parts of the microwave oven, a time display unit 6 for displaying the thawing time under a control of the microcomputer 5, a magnetron 8 for generating a radio frequency wave, and an output control unit 7 for controlling driving of the magnetron 8 under a control of the microcomputer 5.
The operation of the thawing device having the above-mentioned construction will now be described.
When a user lays the food 2 to be thawed on the turntable 3 disposed in the heating chamber 1, the weight sensor 4 disposed beneath the turntable 3 senses the weight of food 2 and generates an electrical signal indicative of the sensed weight. The output signal from the weight sensor 4 is sent to the microcomputer 5 which, in turn, calculates a thawing time for the food 2, based on the received signal. On the basis of the calculated thawing time, the microcomputer 5 controls the time display unit 6 to display the total thawing time and simultaneously sends a control signal to the output control unit 7. In accordance with the control signal from the microcomputer 5, the output control unit 7 activates the magnetron 8 to oscillate. As the magnetron 8 oscillates, radio frequency wave energy is applied to the food 2, thereby causing the food 2 to be thawed.
FIG. 2 is a flow chart illustrating the procedure of calculating the thawing time and controlling thawing of the food 2 based on the calculated thawing time by the microcomputer 5. This procedure will now be described, in conjunction with FIG. 2.
As shown in FIG. 2, first, the microcomputer 5 checks whether a currently input key signal corresponds to an automatic thawing key signal. Where the current input key signal does not correspond to the automatic thawing key signal, a function according to the current input key signal is carried out. Where the current input key signal corresponds to the automatic thawing key signal, the microcomputer 5 checks a door condition of the microwave oven. When the door is at its opened state, the microcomputer 5 returns to the step of checking whether the current input key signal corresponds to the automatic thawing key signal and then begins its control operation again. On the other hand, when the door is at its closed state, the microcomputer 5 receives an output signal from the weight sensor 4 and then calculates a weight Wo of the food 2, based on the received signal. Based on the calculated food weight Wo, the microcomputer 5 also calculates a thawing time Tw for the food 2. Thereafter, the microcomputer 5 controls the output control unit 7 on the basis of the calculated thawing time Tw so that the magnetron 8 begins to oscillate, thereby heating the food 2. When a time taken to heat the food 2 reaches the calculated thawing time Tw, the microcomputer 7 controls the output control unit 7 to stop the oscillation operation of the magnetron 8. Thus, thawing of the food 2 is completed.
However, in the above-mentioned conventional thawing device it is difficult to calculate an:appropriate thawing time because the thawing time is calculated only based on the food weight, without any compensation based on the kind of the food and the frozen degree of the food. Moreover, only a local thawing is accomplished by the conventional thawing device. This is because the magnetron of the thawing device always generates uniform output energy. In some cases, the food is partially boiled.